Degradation of amisulbrom and its metabolite IT-4 in cucumber under field conditions and processing. Issue 1 (2nd January 2018) - Xue, Jiaying
ABSTRACT: The study of the pesticide degradation and residue change is a global challenge during open field growing and processing of agricultural products. In this study, the degradation of a new fungicide, amisulbrom and its metabolite IT-4 in cucumber during field growing, home processing and storage was assessed. A combination method of modified QuEChERS and high performance liquid chromatography-tandem mass spectrometry with average recoveries of 86.3–107.1% and relative standard deviations of 2.9–7.0% was proposed to measure the concentrations of the two compounds in cucumber samples. The half-lives of amisulbrom under field condition were 4.5–5.8 days and the terminal residues ranged from 0.010 mg/kg to 0.11 mg/kg. Results from processing studies showed that gradual reduction of amisulbrom with 5.5–50.9% was presented with the increased operation time and temperature of washing or cooking. There was an obvious loss of 7.3–14.5% for amisulbrom from cucumber when stored at 4°C in dark for 120 h, and 5.8–37.7% reduction of amisulbrom stored at 25°C, respectively, whereas no significant loss of amisulbrom was observed in cucumber samples stored at −20°C. The degradation of reduced amisulbrom residues to IT-4 was only found in cucumber samples during cooking with the concentrations of 0.0011–0.018 mg/kg. All of the processing factors were below 1 indicating these processing procedures could eliminate amisulbrom levels. This work is useful for evaluating degradation of amisulbrom and IT-4 in raw and processed cucumber, and also providing guidance to develop an effective approach for removing pesticide residues from commodities.